SONAR is a technique used to ........

Options

A. detect the submarine inside sea
B. determine the size of blue whale
C. detect the impurities present in sea water
D. detect the depth of sea bed

Explanation

**Step-by-Step Solution:**

1. **Understanding SONAR**: SONAR stands for Sound Navigation and Ranging. It is a technique that uses sound waves to detect and locate objects underwater.

2. **Identifying the Function of SONAR**: SONAR emits sound waves that travel through water. When these sound waves hit an object (like a submarine or the seabed), they reflect back to the source.

3. **Calculating Distance**: The time taken for the sound waves to travel to the object and back is recorded. By knowing the speed of sound in water, we can calculate the distance to the object using the formula:
\[ \text{Distance} = \frac{\text{Velocity} \times \text{Total Time}}{2} \]
This is because the total time includes the journey to the object and back.

4. **Analyzing the Options**: The question provides four options regarding the use of SONAR:
- Detecting submarines inside the sea
- Determining the size of a blue whale
- Detecting impurities in seawater
- Detecting the depth of the seabed

5. **Selecting the Correct Option**: Among the options, the most relevant function of SONAR is to detect the depth of the seabed. This is because SONAR is primarily used for navigation and mapping underwater terrains.

6. **Conclusion**: Therefore, the correct answer is that SONAR is used to detect the depth of the seabed.

**Final Answer**: SONAR is a technique used to detect the depth of the seabed.

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